Lock-joint for automobile wind-shields.



HIELDS.

I s. R. BAIL LOCK JOINT FOR AUTOM ND 8 APPLICATION FILED 1914- I Patented Feb. 15, 1916.

. screw for operating the locking means, but,

To all whom it may concern:

UNITED STATES PATENT orrion.

SAMUEL R. BAILEY, or AMESBURY, MASSACHUSETTS.

' LOCK-JOINT'FOR AUTOMOBILE WIND-SHIELDS.

' l Specification of Letters Patent. Patented Feb; 15, 1916.

Application filed December 14,1914. Serial No. 877,018.

Be it known that I, SAMUEL R. BAILEY, a citizen of the United States, residing at Amesbury, in the county of Essex and State of Massachusetts, have invented an Improvement in Lock-Joints for Automobile lVind-Shields, of which the following is a specification.

This invention relates to certain improvementsin lock joints for wind shields of automobiles, which permit the shield to be adjusted and locked at difierent angles. On account of the great strain which is placed on these joints, due to the wind pressure and leverage through which this force acts, much difficulty has been encountered in producing joints of this character which are not liable to slip or to become loosened, and, at the same time, to produce a joint which may 'be readily unlocked and readjusted. For

obvious reasons, it is desirable, .in devices of this character, to employ a slmple thumb with many of these devices, it has been cure the necessary, frictional-engagement, by this means, to lock the joint with suflicient security, or, if this difficulty was obviated, to obviate the almost equallyobjectionable difficulty of having the parts of the joint bind, so that they could not be readily moved after they had been unlocked or released. It has further been ascertained that a, simple set-screw, operating in the ordinary way, is

generally inadequate for the purposeeven though if tightened with a wrench, which is objectionable, as it isinconvement, and par ticularly so on account of the fact'that quite frequent, and often quick} adjustments are necessary. Moreover, an ordinary set-screw, while perhaps the simplest form of locking j means which may be employed, is o-bjection able, if frequent adjustments are necessary, for the reason that both the screw and the partengaged, soon become mutilated so that the screw cannot perform its function, even though it is tightened with such force as to twist it apart,'or to strip the thread, A simple construction, i in this connection, is, however, particularly desirable.

The objectsof my invention are to produce a lock j oint of the 'abovedescribed character, which is of such simple construction that it maybe manufactured at small. expense, and willbe unlikely-to get outiof order, which is adapted to lock the parts, through the medium of a thumb screw, so

that they will not become loosened under any condition of use to which they are likely to be subjected, or is adapted to lock them partially, so that a friction joint is produced, which is adapted to be readily unlocked, so that the parts may be readjusted, and in whichthe tendency of thelocking surfaces to bind, after they have been un-v locked, is practically obviated. I accomplish these objects by the means shown in the accompanying drawing, in which Figure 1 is a front elevation of a wind shield provided with'joints embodying-my.

invention. Fig. 2 is a side elevation of an' outer slde of a lock oint embodying my in-' vention,. Fig. 3 is a side elevation of the lnner side thereof. Fig. at is a cross sectional new on the line 4% of Fig. 3. Fig.

5 is a detail sectional view on the'line 55 of Fig. 3.

Joints of this character are usually employed in pairs, and, in the present instance, found that, either it was not possible to se thepartsthereof are held inposition by the.

.wind shield, or dasher 50, and require no other holding means. As these joints, aside from the fact that they are made as rights and lefts, are identical, the description will be confined to a single joint.

sol

In the drawing, a indicates the fixed mem her, which is provided with a cylindrically shaped head-portion (4', having a circular chamber a in the inner side thereof, and b the movable member having a cylindrically. shaped trunnion Z), which is adapted to'fit freely, and to rotate easily in the chamber a According to my invention, I provide a thumb screw 2, which is threaded in aboss on the fixed member a in an oblique position,

with relation to the outer side'thereof, and

an intermediate point, the peripheral. surf'.

face of the trunnion b, so that said face will be. forced, when the screw is moved" axially, obliquely against the trunnion land will therefore have a wedging action to force the trunnion against the oppositeside of the 3-j= l i l chamber a from that at which it is engaged by said screw.

The circular side wall of the trunnion.- receiving chamber a iscut away toprovide a segmental recess which is about a quadrant in length, and the middle point of which is approximately, thouglrnot necessarily exactly diametrically opposite the point of con.- tact of the conical face 0 with the trunnion, so that no bearing surface is provided for the peripheral portion of the trunnion next said recess a and converging bearingsurfaces a are provided therefor at the ends of said recess.

With the above-described construction, when the screw 0 is screwed inwardly, the wedging action of its conical face 0'', on the trunnion, will act to force the latter into the recess a to a slight extent, and, as the depth of said recess is such that the trunnion cannot engage the bottom thereof, it follows that the entire wedging force on the trunnion will be effective in pressing the same against the surfaces a between which it will become wedged and securely locked. By this means, the trunnion is locked against rotation much more effectively than it would be if the entire wall of the chamber were cylindrical, for the reason that, if the recess were not-provided, there would be practically only one point at which the trunnion would be pressed with the maximum force, against the side of the cylindrical cavity which receives it, which point would be diametrically opposite the point of engagement of the locking screw with the trunnion, or in the line in which the trunnion is forced by the locking screw; while, with applicants construction, the full force of engagement is applied at two points, giving a greater frictional surface. Moreover, the curved surface of the trunnion is not forced perpendicularly against the correspondingly curved internal surface of the fixed member, but it is forced obliquely against said surface, at the two points of contact, so that a mechanical advantage is secured through the wedging effect, which greatly increases the effectiveness of the lock,

for a certain force. In like manner, the wedging effect of the tangentially arranged screw results in causing the trunnion. to be pressing against the opposite side of the 'trunn1on-rece1vin cup with much greater force than it would be pressed, by the same force, if the action were direct, or in a radial line, and, as a consequent result, the frictional engagement of the screw withthe peripheral face portion of the trunnion,'which is directly engaged thereby, is also much stronger than if the action were direct. As

these points of frictional engagement with the trunnion are all on its periphery, the maximum holding eifect thereon is secured. For these reasons, the joint will be securely locked in, any position to which it may be adjusted with a comparatively small expenditure of force, or with the force which may be easily applied with the fingers.

'lVhen the locking screw is unscrewed, it

is positively carried out of engagement with the trunnion, thus permitting the latter to ,move ;out of locking engagement withthe may bemanufactured at low cost. Further,

there are no loose parts which are likely to be lost and 'there'is no mechanism which is likely to get out of order. The device is also durable, as the wedging engagement of the locking screw 1 does not tendto cut. the surface of the trunnion, so that it is likely to become mutilated, orso that the locking effect of the parts may becomeimpaired.

As the locking is entirely frictional, and not positive,-the joint may be adjusted with-.

out unscrewing the screw 0, provided said screw has not been tightened to too great an extent.

It will be understood "that the terms fixed and movable used in the claims to distinguish the members of the joint, are

merely relative; although, as a matter of convenience, the specific arrangement, shown in Fig. l, is preferable.

1. A lock joint comprising a fixed and movable member,-sa1d movable member having a .trunnion rotatably 'mounted' in the fixed member, and a locking screw threaded in'the fixedmemberand obliquely movable with. relation to the peripheral surface of. the trunnion, into wedging engagement therewith, to lock the trunnion against rota-.

tion. I V v 2. A lock joint comprising a fixed Z-member, a movable member "having .a trunnion" journaled therein, and a locking screw threaded in said fixed member in an: axially tangential relation with the peripheral surface of the trunnion, said screw havingan engaging gface thereondisposed to be moved into wedging engagement with said peripheral surface. V j

3. A lock joint comprising a fixed. and a movable member, said movable member having a trunnion journaled in: the fixed mem y her, a locking screw threaded in said "fixed.

member in an approximately axially tangential relatlon with the peripheral surfacerof the trunnlon and having aconlcal face at its.

end disposed to be moved'into 'wedging en-l convergently arranged with relation to an adjacent portion of said peripheral surface,

and movable into wedging engagement therewith, to lock the trunnion.

5. A look joint comprising a movable member having a trunnion, a fixed member provided with a circular bearing chamber to receive sald trunnlon, and having a segmental recess leading from its bearing sur face, to form converging bearing portions for the trunnion at the ends of saidrecess, and a locking device disposed to force said trunnion laterally between saidbearing portions and wedge the same therebetween. V

g 6. A look joint comprising a movable member havinga trunnion, a fixed member provided with a circular bearing chamber to receive said trunnion, and having a segmental recess leading from its bearing surface to form converging bearing portions for the trunnion at the ends of said recess, a locking-screw threaded in said fixed member and movable into frictional engagement with the peripheral surface of the trunnion at points diametrically opposite said recess, to force the trunnion into frictional engagement with said converging bearing portions of the fixed member.

7. A lock joint comprising a movable member having a trunnion, a fixed member provided with a circular bearing chamber to receive said trunnion, and having a segmental recess leading from itsbearing surface, to form converging bearing portions" for the trunnion at the ends of said recess, a

in tangential relation to the peripheral surface of the trunnion, having a tapering face,

convergently arranged with relation to a peripheral surface portion of the trunnion, disposed diametrically opposite the portion next said recess and movable into wedging engagement therewith, to forcesaid surface of the trunnion into wedging engagement with said bearing portions of the fixed member.

In testimony whereof, I have signed my name to this specification, in'the presence of two subscribing witnesse Witnesses:

L. H. HARRIMAN, H. B. DAVIS.

Copies of this patent may be obtained for five-cents each, by addressing the Commissioner of Patents, Washington, I). C.

SAMUEL R. BAILEY."

45 locking-screw threaded in said fixed member 7 

